Pressure dependence of out-of-plane resistivity ρc has been investigated in an optimally-doped high-Tc cuprate La2-XSrxCuO4. By applying pressure, we found a drastic decrease in ρc which reaches 50% at P=8 GPa. This surprisingly large P dependence implies that the thermal contraction along the c axis is significantly reflected in the ρc(T) curve, leading to a metal-like term; hence La2-XSrXCuO4 is essentially characterized as a two-dimensional metal modified with nonmetallic conduction between CuO2 layers. Tun-neling is suggested for a possible mechanism for ρc.